Beer processing and composition

ABSTRACT

A composition that provides improved chillproofing of beer and other beverages is disclosed. The composition comprises a silica gel reacted with a metal, said metal having the capability of being sorbed and desorbed from the silica gel in response to pH and concentration changes.

This application is a Continuation-in-Part of applicants' co-pendingU.S. patent application Ser. No. 7/420,502, filed Oct. 12, 1989, nowabandoned.

BACKGROUND OF THE INVENTION

Compositions comprising silica gel reacted with metal ions provideimproved chillproofing and processing of beer and other brewedbeverages. The compositions provide processing advantages with mostbeers but are especially useful in treating the so-called high malt beerand other beers that are known to be difficult to chillproof.

The term "beer," as used in this specification and claims, includes manytypes of brewed beverages. Such beverages include lager, Pilsner,Dortmund and Munich beers. Other such beverages are ale, porter andstout.

Beer and other beverages brewed from grains are complex solutionscontaining numerous organic solutes. Some of these compounds undergoreactions depending on how and how long the beverage is stored. Onetroubling reaction is the development of haze on aging and chilling.This haze is objectionable to consumers of the beverage.

A number of methods and products have been developed to removesufficient of the haze former to prevent its formation. These methods orproducts are used before bottling and include the use of variousadsorbents such as silica hydrogels and/or xerogels; calcium, aluminumand magnesium silicates; several types of clays or minerals; andmixtures thereof. U.S. Patents that disclose such art include U.S. Pat.Nos. 3,163,538; 3,251,693; 3,436,225; 3,617,301; 3,940,498; and3,958,023. U.S. Pat. No. 4,797,294 discloses a combination of silica geland magnesium silicate as an effective chillproofer for some beers.

Not all beers are equally easy to stabilize against chill hazeformation. Sfat, "MBAA Technical Quarterly" 12, 4,243-248 (1975),teaches that some beers can be stabilized with 1 to 2 pounds ofpolyvinylpolypyrollidone (PVPP) and 3 to 4 pounds of silica gel for each100 bbls of beer. More difficult beers require 3 to 4 pounds of PVPP and3 to 4 pounds of silica hydrogel for each 100 bbls of beer for effectivestabilization.

It is an object of this invention to provide a chillproofing agent thatis effective in beers that are difficult to treat and that can be usedwith shorter contact times or in lower doses for beers that are easierto chillproof. It is also an objective of this invention to provide amethod and product that do not involve PVPP in chillproofing higher maltbeers.

SUMMARY OF THE INVENTION

The chillproofing composition of our invention is prepared by reactingcertain alkaline silica gels with metals. Such compositions areexceptionally effective in chillproofing all beers, but are especiallyuseful for beers which have previously required a combination of silicagel and PVPP to stabilize. The metal ion is reacted with or sorbed onthe silica gel to provide a uniform distribution of the metal in thepores and on the surface of the silica.

The composition of our invention is added to the beer before bottling.Contact continues for a time sufficient to adsorb the chill hazecomponents and provide the degree of stabilization required. Use of thecomposition of our invention allows processing of most beers at lowerdosages or at shorter contact times than required when silica hydrogelis used. High malt beers can be processed without the use of PVPP.

The increased chillproofing activity of the product made by our processhas not been predicted by the prior art that discloses various siliceousagents that contain metals. The prior art discloses blends of silica geland magnesium silicate which have only slightly higher chillproofingactivity than silica gel alone in difficult to stabilize high maltbeers. Our product, which contains sorbed or exchanged multivalent ions,is extremely efficient in chillproofing such beers. Indeed, the metalmust be introduced into our products as described, as other ways ofproviding metal do not provide the desired chillproofing activity. If asilica gel suspended in a solution of metal salt is used forchillproofing, the desirable behavior of our product is not realized. Ifa metal silicate is introduced into a silica hydrosol, the chillproofingactivity of the resulting gel is lost.

THE INVENTION

The composition of our invention is a silica gel wherein metals,especially those with multivalent ions, are reacted with or sorbed onthe gel. Our composition is characterized by a uniform distribution ofthe metal in the pores and on the surface of the silica. Our compositionis further distinguished in that the metal is not in the form of largeprecipitates of metal oxide that block the pores of the silica, nor ismetal oxide precipitated around the particles of silica.

The first step in forming the composition of our invention is thepartial neutralization of a sodium silicate or potassium silicatesolution to form a silica hydrosol. We prefer to neutralize 60 to 85% ofthe alkali metal present in the silicate solution. A most preferredembodiment is to neutralize 70 to 80% of the alkali metal in thesilicate solution. This hydrosol is allowed to set to a hydrogel. Thehydrogel is slurried with a solution of a salt of a multivalent metaland an acid, the pH and concentration of said solution being such thatthe metal reacts readily with the silica hydrogel, but does notprecipitate. The silicate may be completely neutralized or induced togel with an excess of acid and washed if the gel is adjusted to analkaline pH prior to treating with the metal solution.

Multivalent metals used to prepare the compositions of our invention arethose which can react with the silica surface in a reversible manner. Inother words, the metal ion must be capable of sorbing or desorbing fromsilica in response to changes in pH and/or concentration. Among usefulmetals are aluminum, calcium, magnesium, nickel, barium, manganese,copper and mixtures thereof. The metal can exist in the solution as theionized form of a metal salt. The metal can also be present as acomplex. We use halides, phosphates, nitrates, sulfates, acetates oroxalates as counter ions to the metal ions in solution. Theconcentration of the metal ion in solution should be sufficient topromote reaction of the metal with the silica but not favorprecipitation or aggregation of metal species. The concentration of themetals as the ion should be more than about 0.3% by weight but less thanabout 10% by weight. We prefer 3 to 7% by weight.

The pH of the metal ion solution must be controlled and may be adjustedduring the reaction of the metal with the silica, and the pH-adjustingagent may be any that can achieve and maintain the required pH value insolution while the solution is exposed to silica. Acids, bases andvarious buffers can be used. For most metals the pH should be maintainedat a value of about 7 to 10.5; we prefer 8 to 9.5.

The reacted gel is separated from the spent solution by any convenientmethod. The product is washed to reduce salt concentration. The productis then dried and milled to finish the process.

The preparation of our product can be described in further detail withmagnesium as the metal. Silica hydrosols are prepared by simultaneouslyand instantaneously mixing aqueous solutions of acid and sodiumsilicate. The concentrations and flow rates or proportions are adjustedso that the hydrosol contains 8 to 12% SiO₂ and so that only 60 to 85%of the sodium is neutralized. Such hydrosols gel rapidly and can beallowed to gel in a mass and then crushed to form particles for furtherprocessing. In one embodiment the hydrosol contains about 10% SiO₂, hasa pH above about 8 and gel in a matter of seconds or less. Such ahydrosol can be formed into spheres by spraying in air.

The gel particles are contacted with an aqueous solution of a magnesiumsalt such as MgSO₄ for a period of time sufficient to replace theunreacted sodium on the surface of the silica with magnesium. Thecontact time can be 1 to 6 hours. The gel is then washed, dried andmilled to provide the desired moisture level and particle size. Theparticle size should average 10 to 40 microns.

Another process embodiment of the process to prepare the product of ourinvention involves the preparation of a silica gel wherein the hydrosolhas a neutral or acid pH value. Sufficient or more than sufficient acidis added to neutralize all of the sodium present in the silicate. Theresulting gel is washed to remove some salts and excess acid. Then analkaline solution such as NaOH is added to the silica gel slurry toprovide a pH above about 8, preferably between about 8.3 and 9. Thisalkalized or alkaline gel is contacted with a solution of a metal saltsuch as magnesium sulfate for a time sufficient to exchange and/or reactthe magnesium on the silica surface in place of the sodium.

In the preferred embodiment of our invention, the exchanged or reactedsilica gel is dried. In another embodiment of our invention theexchanged or reacted gel can be used without drying or can be partiallydried.

The product of our invention comprises a silica gel reacted with ametal, usually a metal with a valence of 2 or more. The metal isapparently distributed uniformly from the center of each particle orgranule to the surface, and it is not in the form of a large metal oxideprecipitates either in the pores or around the particles. The amount ofmetal reacted varies, but should be more than 0.65% wt/wt. The productcan contain 5 to 60% moisture with the balance being SiO₂. A preferredproduct of our invention has the following composition:

    ______________________________________                                                   % by Weight                                                        ______________________________________                                               Metal 0.7-15.0                                                                SiO.sub.2                                                                           60.0-94.0                                                               H.sub.2 O                                                                           5.0-25.0                                                         ______________________________________                                    

Our most preferred metal ion is magnesium, and we prefer to have about 1to 5% present as Mg.

The first advantage of the product of our invention is exceptionallyefficient chillproofing of beer and brewed beverages. In one experimenta commercially available silica hydrogel beer clarifier requiredsufficient product to yield 1500 ppm of SiO₂ to provide a chill hazereading after forcing of 38 ASBC FTU. A composition of our inventioncontaining magnesium provided an FTU reading of 23 at only 600 ppm ofsolids. To chillproof beer, 200 to 1500 ppm of the composition of ourinvention is introduced into the beer and allowed to contact the beerfor a sufficient time to remove the chill haze elements. The spentcomposition is removed and the beer is now stabilized.

A second advantage of the product of our invention is that it canchillproof beers that cannot be stabilized by any dosage of silica gelalone. The dosage of our product required for these beers is not inexcess of the usual 200 to 1500 ppm recited previously. Anotheradvantage of our product is its rate of action. Our product chillproofsfaster than silica hydrogel, as shown in Example 6.

Numerous methods of providing a combination of metals with silica gel tothe chillproofing process have not provided behavior even approachingthe efficiency of the product made by our process. A suspension ofsilica gel in a solution of magnesium sulfate does not exhibit theactivity of our composition. For details see Example 4. Blends ofmagnesium silicate and silica gel have only slightly improvedchillproofing activity when compared with silica gel alone, when used inhigh malt, difficult to chillproof beers. Our product provides muchimproved performance over a commercial silica hydrogel as is shownExample 2. Silica gel made with magnesium silicate fed to the hydrosolprior to gelling is actually inferior to silica gel in chillproofingactivity.

EXAMPLES

The following examples illustrate certain embodiments of our invention.These examples are not provided to establish the scope of the invention,which is described in the disclosure and recited in the claims. Theproportions are in parts by weight (pbw) or percent by weight (% wt/wt)unless otherwise indicated.

Our chillproofing experiments were carried out as follows. Untreatedbeer was refrigerated at 0° C. during storage and handling, andprotected against oxygen by CO₂. The headspace O₂ level was less than100 ppb during all handling. Time contact with the chillproofing agentstarted when an aliquot of beer was transferred into a tank containing astirred deoxygenated slurry of chillproofer. The slurry contained 10%(w/v) chillproofing agent, and the volume was varied to provide the doseof agent desired. After the required contact time the beer slurry waspumped through a filter. After filtering, the beer was bottledanaerobically against CO₂ back pressure. The bottled beer was forced byincubation at 60° C. for 5 days; then it was stored at 0° C. for 2 days.

The haze was measured with an LG Automatic Haze Meter filled with icewater. The units are ASBC FTU. The instrument is standardized each dayusing membrane filtered water and a 431 FTU standard.

EXAMPLE 1

A silica hydrosol containing 10% SiO₂ was prepared by instantaneouslymixing solution of sulfuric acid and sodium silicate. The acid solutioncontained 19.71% H₂ SO₄. The silicate solution has 3.17 Pbw of SiO₂ foreach pbw of Na_(O) and contained 16.05% solids. The flow rates to thenozzle mixer were such that the hydrosol contained 10% SiO₂, 75% of thesodium in the silicate was neutralized, and the pH was above about 8.The hydrosol was sprayed into the air and allowed to form into spheres.The gel time was less than one second.

The gelled spheres were introduced into an aqueous solution of magnesiumsulfate. The sulfate solution contained 5% MgSO₄ and upon addition ofthe silica gel had a pH of about 8.5 which persisted during the threehour contact time. The reacted gel was washed three times with deionizedwater to remove the sodium salts formed and the residual magnesiumsulfate salts. The volume of water used in each wash step equaled thevolume of the reacted gel. The gel was dried to a loss on drying (LOD)of 15% and milled to an average particle size of 17 microns. The productcontained 2.5% MgO which is equivalent to the sodium which was notneutralized.

EXAMPLE 2

The product produced as described in Example 1 and silica hydrogel, acommercially accepted chillproofing agent, were tested for chillproofingactivity in a difficult to chillproof 80% malt beer.

                  TABLE 1                                                         ______________________________________                                        Chill Haze After Forcing                                                      (ASBC FTU)                                                                                             Commercial                                                          Product   Silica                                               Dose (ppm)     Example 1 Hydrogel                                             ______________________________________                                        None           425       425                                                  200            200       240                                                  400            140       210                                                  600             95       150                                                  800             85       140                                                  ______________________________________                                    

A chill haze of 100 FTU is often a goal which is believed to providedesirable stability for beer. These results indicate that 100 FTU can beachieved by a reasonable dose of our product, 600 ppm. The commercialhydrogel did not provide such a reading even at a dose of 800 ppm.

EXAMPLE 3

The product of Example 1 and the commercial silica hydrogel were testedin a less difficult-to-chillproof 70% male beer.

                  TABLE 2                                                         ______________________________________                                        Chill Haze After Forcing                                                      (ASBC FTU)                                                                                             Commercial                                                          Product   Silica                                               Dose (ppm)     Example 1 Hydrogel                                             ______________________________________                                         0             495       495                                                  200            140       190                                                  400            90        160                                                  600            80        100                                                  800            78        100                                                  ______________________________________                                    

These results also indicate the efficiency of our product in providing aFTU of 100 or less. Our product requires less than 400 ppm to achieve100 FTU, while the commercial silica hydrogel requires 600 ppm.

EXAMPLE 4

The product of our invention as described in Example 1 was tested andcompared with silica gel and a silica gel suspended in a solution ofMgSO₄. Sufficient MgSO₄ was used to provide the same level of Mg that isprovided by the product of our invention. The 80% malt beer was treatedwith 778 ppm of each agent. The results are summarized in the followingtable.

                  TABLE 3                                                         ______________________________________                                        Chill Haze After Forcing                                                      (ASBC FTU)                                                                                      Forced                                                      Treatment Agent   Chill Haze                                                  ______________________________________                                        None              777                                                         Silica Hydrogel   330                                                         Silica Gel + MgSO.sub.4                                                                         323                                                         Product of Example 1                                                                            206                                                         ______________________________________                                    

These results indicate that the silica gel suspended in a solution ofMgSO₄ provided about the same chillproofing 70% performance as did thesilica gel. The product of our invention provided significantly betterchillproofing performance.

EXAMPLE 5

A product similar to that described in Example 1 was prepared withcalcium as the metal. Nitric acid was substituted for the sulfuric acidand the gel contained 10% SiO₂. Twenty-five percent (25%) of the sodiumwas unneutralized. The gel was contacted with a solution of 0.5 molarcalcium nitrate. The other steps remained the same. It was tested withthe product of Example 1 and silica gel in a difficult-to-chillproofbeer with 70% malt. The results are summarized in the following table.

                  TABLE 4                                                         ______________________________________                                        Chill Haze After Forcing                                                      (ASBC FTU)                                                                              Product      Product   Silica                                       Dose (ppm)                                                                              Example 1    Example 5 Gel                                          ______________________________________                                         0        279          279       279                                          400        98          95        --                                           600 --    89            93                                                    ______________________________________                                    

These results with others show that the products made by our process canachieve the desired reading of 100 FTU at a dose of about 400 ppm.

EXAMPLE 6

The product of our ,invention as described in Example 1 (400 ppm) and asilica hydrogel (400 ppm) were used to stabilize beer with 80% malt. TheFTU readings for various total contact times are summarized in thefollowing Table.

                  TABLE 5                                                         ______________________________________                                        Chill Haze After Forcing                                                      (ASBC FTU)                                                                    Total                                                                         Contact Time    Silica  Product of                                            (Minutes)       Gel     Example 1                                             ______________________________________                                        0               402     402                                                   2.08            --      270                                                   2.77            322     --                                                    2.82            346     --                                                    3.41            --      200                                                   6.18            --      209                                                   6.86            273     --                                                    11.53           232     --                                                    11.96           --      174                                                   ______________________________________                                    

These results indicate that our product is very effective in shortcontact times. Our product provides an FTU reading of 270 in about 2minutes while the silica gel requires about 7 minutes to provide thesame reading.

We claim:
 1. A composition for treating beer to prevent chill haze, saidcomposition comprising a silica gel reacted with a multivalent metal ionand being characterized by a uniform distribution of the metal in thepores and on the surface of the silica, and wherein said multivalentmetal is not precipitated in the pores of the silica or around theparticles of silica, said composition being prepared by the steps of:a.combining a solution of sodium silicate or potassium silicate with asolution of an acid to form a silica hydrosol, the composition andproportions of said silicate and acid solution being such that 60 to 85%by weight of the sodium or potassium in the silicate solution isneutralized and the hydrosol contains 8 to 12% by weight SiO₂ ; b.allowing said hydrosol to set to a hydrogel; c. granulating saidhydrogel into discrete particles; d. contacting said hydrogel particleswith a solution of 3 to 10% by weight of a salt of a multivalent metaland maintaining the pH of the mixture of hydrogel and solution at avalue of about 7 to 10.5, whereby the metal reacts or exchanges with thesilica but large precipitates of hydrous metal oxide do not form withinthe pores of the silica or around the silica particles; e. maintainingcontact between the hydrogel particles and metal salt solution until thedesired level of metal is reacted or exchanged with the silica; f.washing the reacted silica g. drying and milling the reacted silica; andh. recovering the product silica.
 2. The composition of claim 1 whereinthe silicate is sodiumsilicate and the proportion of silicate and acidsolutions are such that 70 to 80% of the sodium is neutralized.
 3. Thecomposition of claim 2 wherein the metal is magnesium or calcium.
 4. Thecomposition of claim 2 wherein the SiO₂ is about 60 to 94% by weight,the metal is about 0.7 to 15.0% by weight and the water is about 5 to25% by weight.
 5. The composition of claim 4 wherein the metal ismagnesium or calcium.
 6. The composition of claim 2 wherein the silicahas reacted thereon at least 0.65% by weight of the multivalent metal.7. A composition for treating beer to prevent chill haze, saidcomposition comprising a silica gel reacted with a metal ion and beingcharacterized by a uniform distribution of the metal in the pores and onthe surface of the silica, and wherein said multivalent metal is notprecipitated in the pores of the silica or around the particles ofsilica, said composition being prepared by the steps of:a. combining asolution of sodium silicate or potassium silicate with a solution of anacid to form a silica hydrosol, the composition and proportions of saidsilicate and acid solution being such that at least sufficient acid ispresent to neutralize all of the sodium or potassium in the silicatesolution; b. allowing said solution to set to a hydrogel; c. granulatingsaid hydrogel into discrete particles; d. washing said gel; e. adjustingthe pH of said washed gel to an alkaline value. f. contacting saidhydrogel particles with a solution of 3 to 10% by weight of a salt of amultivalent metal and maintaining the pH of the mixture of hydrogel andsolution at a value of about 7 to 10.5, whereby the metal reacts orexchanges with the silica but large precipitates of hydrous metal oxidedo not form within the pores of the silica or around the silicaparticles; g. maintaining contact between the hydrogel particles andmetal salt solution until the desired level of metal is reacted orexchanged with the silica; h. washing the reacted silica; i. drying andmilling the reacted silica; and j. recovering the product silica.
 8. Thecomposition of claim 7 wherein the silica has reacted thereon at least0.65% by weight of the multivalent metal.
 9. The composition of claim 7wherein the metal is magnesium or calcium.
 10. The composition of claim7 wherein the SiO₂ is about 60 to 94% by weight, the metal is about 0.7to 15.0% by weight and the water is about 5 to 25% by weight.
 11. Thecomposition of claim 10 wherein the metal is magnesium or calcium.
 12. Amethod to treat beer to prevent chill haze comprising contacting saidbeer with 200 to 1500 parts per million (ppm) of metal reacted silicagel for a time sufficient to remove chill haze components from the beerand then separating the composition from the beer wherein said metalreacted silica is prepared by the steps of:a. combining a solution ofsodium silicate or potassium silicate with a solution of an acid to forma silica hydrosol, the composition and proportions of said silicate andacid solution being such that 60 to 85% by weight of the sodium orpotassium in the silicate solution is neutralized and the hydrosolcontains 8 to 12% by weight SiO₂ ; b. allowing said hydrosol to set to ahydrogel; c. granulating said hydrogel into discrete particles; d.contacting said hydrogel particles with a solution of 3 to 10% by weightof salt of a multivalent metal and maintaining the pH of the mixture ofhydrogel and solution at a value of about 7 to 10.5, whereby the metalreacts or exchanges with the silica but large precipitates of hydrousmetal oxide do not form within the pores of the silica or around thesilica particles; e. maintaining contact between the hydrogel particlesand metal salt solution until the desired level of metal is reacted orexchanged with the silica; f. washing the reacted silica; g. drying andmilling the reacted silica; and h. recovering the product silica. 13.The method of claim 12 wherein the silicate is sodium silicate and theproportion of silicate and acid solutions are such that 70 to 80% of thesodium is neutralized.
 14. The method of claim 13 wherein the silica hasreacted thereon at least 0.65% by weight of the multivalent metal. 15.The method of claim 13 wherein the metal is magnesium or calcium. 16.The method of claim 13 wherein the metal reacted silica contains 60 to94% by weight SiO₂, about 0.7 to 15.0% by weight metal and about 5 to25% by weight water.
 17. The method of claim 16 wherein the metal ismagnesium and the beer contains at least 70% malt.
 18. A method to treatbeer to prevent chill haze comprising contacting said beer with 200 to1500 parts per million (ppm) of metal reacted silica gel for a timesufficient to remove chill haze components from the beer and thenseparating the composition from the beer wherein said metal reactedsilica is prepared by the steps of:a. combining a solution of sodiumsilicate or potassium silicate with a solution of an acid to form asilica hydrosol, the composition and proportions of said silicate andacid solution being such that at least sufficient acid is present toneutralize all of the sodium or potassium in the silicate solution; b.allowing said hydrosol to set to a hydrogel; c. granulating saidhydrogel into discrete particles; d. washing said gel; e. adjusting thepH of said washed gel to an alkaline value; f. contacting said hydrogelparticles with a solution of 3 to 10% by weight of a salt of amultivalent metal and maintaining the pH of the mixture of hydrogel andsolution at a value of about 7 to 10.5, whereby the metal reacts orexchanges with the silica but large precipitates of hydrous metal oxidedo not form within the pores of the silica or around the silicaparticles; g. maintaining contact between the hydrogel particles andmetal salt solution until the desired level of metal is reacted orexchanged with the silica; h. washing the reacted silica; i. drying andmilling the reacted silica; and j. recovering the product silica. 19.The method of claim 18 wherein the silica has reacted thereon at least0.65% by weight of the multivalent metal.
 20. The method of claim 18wherein the metal is magnesium or calcium.
 21. The method of claim 18wherein the metal reacted silica contains about 60 to 94% by weightSiO₂, about 0.7 to 15% by weight metal and about 5 to 25% by weightwater.
 22. The method of claim 21 wherein the metal is magnesium and thebeer contains at least 70% malt.
 23. A composition for treating beer toprevent chill haze, said composition comprising a silica gel reactedwith a multivalent metal ion, being characterized by a uniformdistribution of the multivalent metal in the pores and on the surface ofsaid silica gel and wherein said metal is not precipitated in the poresof said silica gel or around the particles of said silica gel, and beingfurther characterized as comprising 60 to 94% by weight SiO₂, 0.7 to 15%by weight said multivalent metal and 5 to 25% by weight water.
 24. Thecomposition of claim 23 wherein the silica gel has reacted thereon atleast 0.65% by weight of said multivalent metal.
 25. The composition ofclaim 24 wherein the metal is magnesium.